As I am paid by the minute and not by the mile, I'm not too concerned if the airplane ahead of me needs a minute or two for whatever reason.
Common courtesy suggests, though, that you shouldn't pass the last escape from blocking the runway without numbers if possible.
In my experience, 80 percent of the time the numbers come right after pushback as the first engine is being started, and 99.9 percent of the time all checklists are complete by the time I'm cleared for takeoff. In that rare, rare case when I'm not ready I've found the following to work: "Tower, we need a few more minutes, what would you like us to do?"
Would that make anyone angry if they heard that? If so, I believe the problem is yours, not mine.